Devices for drawing in a web of material

ABSTRACT

A device for drawing a web of material into a machine, such as a printing press includes a draw-in mechanism that can be advanced along a draw-in path, and to which the web of material can be coupled. The draw-in mechanism can be driven by an electric motor that can be regulated or controlled in response to measurement data which is determined during the draw-in process. The motor can be regulated or controlled in synchronism with another unit of the machine, which other unit is mechanically driven independently of the electric motor.

[0001] The invention relates to devices for drawing a web of material into a processing machine in accordance with the preamble of claim 1, 5 or 6.

[0002] Devices of this type are employed in printing presses for conveying the start of a web of material along the desired draw-in path through the printing press. This is required, for example, for a draw-in in connection with a new production, or always in the case where a web of material was torn during the printing process, because then the start of the new web of material cannot be pulled through in the manner of a flying roll change. Furthermore, in modern printing presses the printing groups can be traveled along different conveying paths in order to be able to obtain correspondingly different printing results, so that in case of a change-over the fresh web of material must be drawn in along the appropriate draw-in path.

[0003] A device for drawing a web of material into a processing station is known from DE 94 15 859 U1, wherein the draw-in means in the shape of a tape can be rewound from of winding roll at the inlet of the processing station to a winding roll at the outlet of the processing station.

[0004] A device for drawing webs of material into rotary printing presses is known from DE 22 41 127 A1, wherein the draw-in means, which is embodied in the form of a spring steel strip, can be pushed from the outlet of the printing press along different draw-in paths, between which switching can be performed by means of shunts. In this case the draw-in means is driven by a stationarily arranged drive wheel, which comes into positive contact with the draw-in means and pushes the draw-in means along its entire length through the printing press.

[0005] EP 0 418 903 A2 discloses a device for drawing in a web of material, wherein a draw-in means is driven by a motor which is controlled as a function of measured data obtained in the draw-in process. Control is performed with a view to a constant draw-in speed, or number of revolutions.

[0006] A device for drawing in a web of material is disclosed in DE 94 09 390 U1, wherein a draw-in means is driven by a step motor. A conveying distance already traveled by the draw-in means is detected by means of sensors.

[0007] The object of the invention is based on providing devices for drawing in a web of material.

[0008] In accordance with the invention, this object is attained by the characteristics of claims 1, 5 or 6.

[0009] A particular advantage of the invention lies in that the flexibly and finitely embodied draw-in means can be wound onto a reel body, so that only little space is required for storing the portion of the draw-in means not pushed into the printing press.

[0010] The embodiment as a finite draw-in means, which can be fastened with one end on a reel body and can be completely wound on, has a great advantage, because in contrast to endless or re-windable draw-in means it is possible here to realize different draw-in paths via shunts.

[0011] Basically the driving of the draw-in means can be assured in any arbitrary manner. In accordance with a preferred embodiment, the draw-in means is driven by the driven reel body, which can be driven in two directions of rotation for winding, or unwinding, the draw-in means. Thus, a separate drive wheel for driving the draw-in means can be omitted.

[0012] Preferably a controllable electric motor is employed for driving the reel body, so that the reel body can be driven in a controlled manner at different rotational speeds and/or torques. A constant conveying speed, or a comparable moment, can be set at the draw-in means by an appropriate measurement, for example of the feeding speed of the draw-in means, or of the applied moment. However, in a different embodiment the electric motor can also be correspondingly controlled in respect to a speed (for example frequency) or a torque (output).

[0013] Basically a multitude of sensors are conceivable for measuring the conveying speed of the draw-in means. A particularly simple construction results, if the effective circumference of the reel body by means of which the draw-in means is unwound, and the rotational speed of the reel body are measured, or are preset in the form of a graph. The effective circumference of the reel body is understood to be the value resulting from the circumference of the reel body itself and the circumference of the layers of the draw-in means still wound thereon. By evaluating these two measured values it is possible in a simple manner to determine the linearly directed feeding speed of the draw-in means and thereafter to set it to a command value by an appropriate regulation of the rotational speed of the reel body. Also, a corresponding dependence of the command value rpm from the number of revolutions performed, stored in the form of a control curve in the software, is conceivable.

[0014] It is necessary in the course of pushing the draw-in means through the printing press to transmit considerable compressive strains in order to overcome the frictional forces in the guide devices. Therefore the draw-in means can be preferably embodied in the form of a steel tape, in particular a spring steel tape, since steel tapes have great flexibility and at the same time can transmit large tensile or compressive strains. However, the use of known plastic tapes, chains or correspondingly embodied cables is of course also possible.

[0015] In order to reduce the frictional forces occurring at the draw-in means, which must be overcome by the drive mechanism, as much as possible, the draw-in means can be sheathed, at least in part, in a friction-reducing layer. For example, it is possible to sheathe the draw-in means in the form of a steel tape in a layer of plastic in order to combine in this way the material properties of the steel tape of high tensile or compressive resistance with the desired low-friction material properties of the plastic.

[0016] In what follows, an exemplary embodiment of the invention will be represented in the drawings and described in greater detail. They show a printing press with a device for drawing-in a web of material in schematically represented cross section.

[0017] A draw-in device 08, 09, 11 for drawing in the start of the web of material is provided in a processing machine 01, for example a printing press 01, for processing webs of material, for example paper webs.

[0018] The printing press 01, represented in cross section in the drawings, has two printing units 02, 03, each with two double printing groups, or four printing groups, as well as three roll changers 04, 06, 07.

[0019] Three devices 08, 09, 11 for drawing a web of material into the printing press 01 are arranged downstream of the outlet of the printing units 02, 03. Each of the devices 08, 09, 11 consists of a draw-in means 12 embodied in the way of a spring steel tape 12, which can be wound on a reel body 13, which is embodied in a rotationally symmetrical manner.

[0020] In a first exemplary embodiment, the reel body 13 is driven by means of a motor 17, for example an electric motor 17 (only represented in connection with the upper reel body 13), in particular by means of a controllable a.c. motor 17 with a frequency converter. Control is performed in such a way that with a changing reel radius the number of revolutions is changed in such a way that an almost chronologically constant draw-in speed is provided.

[0021] In another mode of operation, regulation can also take place in such a way that the electric motor 17 is operated at any time with a defined presettable moment and in this way results in a largely constant web draw-in. This moment can be constant, for example for short draw-in distances, and for longer draw-in paths it can take place, for example, along a predeterminable curve.

[0022] In a general way the electric motor can be controlled as a function of measured data obtained in the course of the draw-in, which provide data regarding the progress and/or existing moments.

[0023] In a second exemplary embodiment (represented by dashed lines), the draw-in means 12 can be drawn in by means of a synchronous drive mechanism 14 constituted by two rollers enclosing the draw-in means. The synchronous drive mechanism 14 can also have a driven roller and an undriven roller, which can be placed against the latter. The reel body also has a motor which, however, need not be controllable in the way of the previously mentioned electric motor 17.

[0024] In this case the electric motor 17 (dashed lines) is arranged driving the synchronous drive mechanism 14 (dashed lines) and is controlled, the same as above, to provide a constant draw-in speed or a constant, or presettable moment.

[0025] In both examples the reel body 13 has a center shaft on which the one end of the draw-in means 12 is fixed. Moreover, lateral cheeks are provided at the ends of the center shaft against which the portion of the draw-in means 12 wound on the reel body 13 is laterally supported.

[0026] It is also possible to arrange only a single device 08, 09, 11 for draw-in downstream of the outlet of the printing units 02, 03, wherein a selection of the draw-in path can be realized by the arrangement of shunts, not represented.

[0027] By means of driving the reel body 13 in a clockwise direction, the finite draw-in means 12 can be wound off the reel body 13 and pushed, depending on the position of the shunts 16, only schematically represented, along the different draw-in paths through the printing press 01. In the process, the draw-in means 12 is guided by guide rails, not represented. In the area of the inlet to the printing press 01, the draw-in means 12 can be connected with the start of the respective paper web at the roll changers 04, 06 or 07, so that the paper web is conveyed through the printing press 01 by retracting the draw-in means 12 along a desired draw-in path.

[0028] The control of the electric motor 17 driving the reel body 13 in accordance with the first exemplary embodiment can also be applied in connection with devices for draw-in wherein a finite draw-in means 12 is rewound from a reel body, not represented, in the area of the roll changer(s) 04, 06, 07 to a reel changer 13 downstream of the outlet of the printing units 02, 03, and vice versa.

[0029] In an advantageous embodiment, the individual units, for example the cylinders of the printing groups individually or in pairs, the entire printing group of the printing unit, the driven rollers of the paper guide device, the folding apparatus, and possibly further rotatable elements of the printing press, each have their own drive motor. Matching, or synchronization, takes place by means of a so-called “virtual guide axis” or “electronic shaft”, which electrically connects the regulating or control devices of the units with each other. A regulating device (or control device) of the electric motor for the synchronous drive mechanism 14 or the direct drive of the reel body 17 is electrically connected with this “virtual guide axis”, for example in such a way that a speed of the draw-in means approximately corresponds to the respective surface speed of the units in contact with the web, for example the respective cylinders of the printing units 02, 03, the driven paper guide or draw-in rollers (not represented), the roll changers 04, 06, 07, etc.

[0030] For this purpose, the respective number of revolutions, or the angular speed of the electric motor 17 for the synchronous drive mechanism 14, or the reel body 13, is determined in an electronic circuit or computer unit, possibly by using a controllable frequency converter, and present at the electric motor 17. In the reverse manner it is also possible to preset a possibly constant draw-in speed, wherein the remaining units relating to the draw-in process are driven with a corresponding circumferential speed via the electronic shaft. In the case of the direct drive of the reel body 13, the change of the effective diameter must be superimposed on the desired or required draw-in speed in the described way.

[0031] The exemplary embodiment for regulating the electric motor 17 in respect to a moment is directed to a limitation of the stress on the web, or on the connection between the web and the draw-in means 04 during the draw-in process. Here, in case of a directly driven reel body 13, this regulation is performed, as already partially explained above, by taking into consideration the changing diameter. This consideration is taken, for example, in an electronic circuit or computer unit by means of stored functions (for example as a function of the revolutions performed, or of angles, or by means of the above mentioned measured values). In addition, it is possible by means of information regarding the already taken and/or remaining draw-in path determined by measurements or in another way (for example the revolutions made, or the angles) to provide a superimposition of a moment required for overcoming the friction.

[0032] The angular speed, or the number of revolutions, can be detected at the reel body or the electric motor 17 (for example by means of incremental encoders) and, as in the previously mentioned example, can be preset following an appropriate re-calculation via the electronic shaft to the control, or regulating devices of other, individually driven units. However, the determination of the draw-in speed can also be performed in other ways on the draw-in path.

[0033] List of Reference Symbols

[0034]01 Processing machine, printing press

[0035]02 Printing group

[0036]03 Printing group

[0037]04 Roll changer

[0038]05 -

[0039]06 Roll changer

[0040]07 Roll changer

[0041]08 Device

[0042]09 Device

[0043]10 -

[0044]11 Device

[0045]12 Draw-in means, spring steel tape

[0046]13 Reel body

[0047]14 Synchronous drive mechanism

[0048]15 -

[0049]16 Shunt

[0050]17 Motor, electric motor, a.c. motor 

1. A device (08, 09, 11) for drawing in a web of material into a processing machine (01), having a draw-in means (12), which can be conveyed along a draw-in path, to which the web of material can be connected and which can be driven independently of at least one other unit of the processing machine by means of an electric motor (17), characterized in that the electric motor (17) driving the draw-in means (12) and a drive mechanism of the at least one mechanically independent unit are regulated or controlled in relation to each other.
 2. The device in accordance with claim 1, characterized in that the electric drive motor (17) driving the draw-in means (12) can be regulated as a function of measured data determined in the course of the draw-in process.
 3. The device in accordance with claim 1, characterized in that the electric motor (17) can be regulated as a function of a conveying speed of the draw-in means (12).
 4. The device in accordance with claim 1, characterized in that the electric motor (17) is regulated in respect to a presettable moment present at the electric motor (12).
 5. A device (08, 09, 11) for drawing in a web of material into a processing machine (01), having a draw-in means (12), which can be driven by means of an electric motor (17) along a draw-in path, characterized in that the electric drive motor (17) driving the draw-in means (12) is regulated in respect to a presettable moment present at the electric motor (12).
 6. A device (08, 09, 11) for drawing in a web of material into a processing machine (01), having a draw-in means (12), which can be driven by means of an electric motor (17) along a draw-in path, wherein the electric motor (17) can be regulated as a function of a conveying speed of the draw-in means (12) and can be driven independently of at least one other unit of the processing machine, characterized in that the electric motor (17) driving the draw-in means (12) and a drive mechanism of the at least one mechanically independent unit are regulated or controlled in relation to each other.
 7. The device in accordance with claim 1, 5 or 6, characterized in that the electric motor (17) drives a reel body (13), to which one end of the draw-in means (12) is fastened and on which the draw-in means (12) can be wound.
 8. The device in accordance with claim 1, 5 or 6 characterized in that the electric motor (17) drives at least one roller of a synchronous drive mechanism (14), which has two rollers which can be placed against each other.
 9. The device in accordance with claim 1, 5 or 6 characterized in that the draw-in means (12) is embodied to be flexible and finite.
 10. The device in accordance with claim 1, 5 or 6 characterized in that the web of material can be connected to a first end of the draw-in means (12), and the second end of the draw-in means (12) is fastened to a reel body (13) and can be wound on the reel body (13).
 11. The device in accordance with claim 7, characterized in that the electric motor (17) is charged with a moment as a function of an effective circumference of the reel body (13).
 12. The device in accordance with claim 7, characterized in that the electric motor (17) is charged with an angular speed, or a number of revolutions, as a function of an effective circumference of the reel body (13).
 13. The device in accordance with claim 1, 5 or 6, characterized in that the electric motor (17) is charged with a moment as a function of measurement data which define the position and/or speeds of the draw-in means (04).
 14. The device in accordance with claim 1 or 6, characterized in that the conveying speed of the draw-in means (12) is maintained substantially constant.
 15. The device in accordance with claim 1 or 6, characterized in that the conveying speed of the draw-in means (12) can be indirectly or directly measured by means of at least one sensor, and can be regulated to a command value by regulating the electric motor as a function of the results of the measurements.
 16. The device in accordance with claim 1 or 6, characterized in that one or several cylinders of a printing group are driven mechanically independently of the electric motor (17) and is, or are, driven as a function of a number of revolutions of the electric motor (17) or a speed of the draw-in means.
 17. The device in accordance with claim 1 or 6, characterized in that one or several rollers are driven mechanically independently of the electric motor (17) and is, or are, driven as a function of a number of revolutions of the electric motor (17) or a speed of the draw-in means.
 18. The device in accordance with claim 1 or 6, characterized in that a number of revolutions of a mechanically independent roller or of a cylinder and a number of revolutions of the electric motor (17) is determined in correlation with each other via a virtual electronic guide shaft.
 19. The device in accordance with claim 1, 5 or 6, characterized in that the electric motor (17) is embodied as an a.c. motor (17), which is regulated by means of frequency conversion.
 20. The device in accordance with claim 14 or 15, characterized in that the effective circumference and the rotational speed of the reel body (13) are measured for the indirect determination of the conveying speed of the draw-in means (12).
 21. The device in accordance with claim 8, characterized in that the drive moment of the synchronous drive mechanism (14) can be transmitted to the draw-in means (12) substantially free of slippage.
 22. The device in accordance with claim 1, 5 or 6, characterized in that at least one guide element, which maintains the draw-in means (12) on the draw-in path, is provided for guiding the draw-in means (12) along the draw-in path.
 23. The device in accordance with claim 1, 5 or 6, characterized in that the draw-in means (12) is embodied as a steel tape, in particular as a spring steel tape (12). 